Two Color Swirls On Cupcakes

Hi all i did buy a tip i love for swirls on cupcakes it have really nice edges, ok i've tried everything to get 2 colors to come out even or close to it, i usually get one color and part of the other, i've used the take the spatula and put color on both sides of bag, two bag's in 1 bag, two colors in one bag, just doesn't work for me, is there a tip or a double bag where each color comes out seperatly any suggestions welcome. thanks

Take two sheets of plastic wrap and put a blob of icing on each sheet. Roll each sheet up to form a log, twisting one end and leaving one open so the icing will come out. Place both icing rolls in a piping bag fitted with the tip. This eliminates a lot of mess as well.